Hello, I did not search for this as I have never heard of it before. I was in the process of trying out some Amsoil engine flush. So before anything had been added or replaced I opened the oil filler cap to vent oil. I saw a creamy white looking goop on the under side of the filler cap. It looks exactly like cold bacon grease:headbang: . My car is a 1994 Loyale with 171,000 miles. I have only owned it for about 6 months. It does not use any coolant nor does anything leak on the ground at home or work. What could this mystery substance be? The only thing I can think of is I do not drive far enought to work to warm up oil and there is extreme amounts of condensation in crankcase, my drive to work is about 2 miles or 5 minutes. I let car warn up about 5 minutes or so. Any ideas? Thanks Jason

It's just water condensation w/oil. That filler tube sticks way out the top of the engine and when it's cold the water vapor will collect there. Mine does that only in the winter time. I just wipe it off from time to time.

 

-Doug

my guess would be oil and water, the condensation inside of the engine heats to steam and rises to the top of the engine and cools slightly on the cooler under surface of the oil filler cap